The 100-plus workers who died in a fire late Saturday at a high-rise garment factory in Bangladesh were working overtime making clothes for major American retailers, including Wal-Mart, according to workers' rights groups.

Officials in Bangladesh said the flames at the Tazreen Fashions factory outside Dhaka spread rapidly on the ground floor, trapping those on the higher floors of the nine-story building. There were no exterior fire escapes, according to officials, and many died after jumping from upper floors to escape the flames.

As firemen continued to remove bodies Sunday, officials said at least 112 people had died but that the number of fatalities could go higher.

The Tazreen fire is the latest in a series of deadly blazes at garment factories in Bangladesh, where more than 700 workers, many making clothes for U.S. consumers, have died in factory fires in the past five years. As previously reported by ABC News, Bangladesh has some of the cheapest labor in the world and some of the most deplorable working conditions.

"The industry and parent brands in the U.S. have been warned again and again about the extreme danger to workers in Bangladesh and they have not taken action," said Scott Nova, executive director of the Worker Rights Consortium, an American group working to improve conditions at factories abroad that make clothes for U.S. companies. Nova said the fire was the most deadly in the history of the Bangladesh apparel industry, and "one of the worst in any country."

Workers' activists went into the burned-out remains today to document which major retailers were using the Tazreen factory.

They say they found labels for Faded Glory, a Wal-Mart private label, along with labels they said traced back to Sears and a clothing company owned by music impresario Sean "Diddy" Combs.

"There's no question that Wal-Mart and the other customers at this factory bear some blame for what happened in this factory," Nova said.

Nova also said that Wal-Mart "knew exactly what's going on at these facilities. They have staff on site in Bangladesh."

Wal-Mart actually warned of dangerous conditions at the Tazreen factory last year, in a letter posted online by the factory owner.

Wal-Mart told ABC News that the company has not yet been able to confirm that it was still making clothes at the factory.

In a statement, Wal-Mart told ABC News, "Our thoughts are with the families of the victims of this tragedy. ... [F]ire safety is a critically important area of Wal-Mart's factory audit program and we have been working across the apparel industry to improve fire safety education and training in Bangladesh.

"As part of this effort, we partnered with several independent organizations to develop and roll out fire safety training tools for factory management and workers. Continued engagement is critical to ensure that reliable, proactive measures are in place to reduce the chance of factory fires. "

In a statement, Sears disputed reports by activists that it sources clothes from the Tazreen facility. "Our thoughts are with the victims of this tragedy," said the statement. "We can also confirm that Sears Holdings does not source from this factory."

"In addition, Sears recognizes that fire safety is a critical international issue that we intend to address through specialized training for management in those factories that produce merchandise for Sears Holdings."

Worker Rights Consortium said that numbers of the labels of garments found in the factory could be traced back to Sears.

A spokesperson for Combs did not immediately respond to requests for comment.